1. Field of the Invention
The present invention relates to an image processing apparatus and an image processing method, in particular, to an image processing apparatus and an image processing method for preventing paper jam in print output of a color multi-function peripheral.
2. Description of the Related Art
Recently, a color multi-function peripheral (hereinafter, referred to as color MFP) has been highly utilized in offices and print shops. The color MFP has a copy function for copying a document, a PDL function capable of printing out a document created by a host computer, and a sending function for sending a document externally from the color MFP via a network. Additionally, color output is possible for all the functions.
Problems of the print output in the copy function and PDL function of the color MFP include paper jam. A representative example which causes paper jam is rolling-in of paper in a fixing unit. A paper jam may occur as a result of rolling-in, when a rectangle (toner application amount is large) having a high density is drawn at the leading edge in the paper carriage direction, paper is not separated from the fixing unit and the paper is rolled-in when it is separated from the fixing unit after the toner is fixed to the paper by the fixing unit.
In order to solve such a paper jam, an image forming apparatus disclosed in Japanese Patent Laid-Open No. 2001-026162 measures each density of areas adjacent to four sides of bit map data corresponding to a paper size developed on a memory. The apparatus is structured so that the measured densities of the four sides are compared with each other, the bit map data is turned so that the area having the largest density is not positioned at the leading edge of the paper, and then the data is printed out.
That is, a peripheral part image density processing part detects each average density of peripheral parts of the four sides of an image for one page which is formed based on digital image signals stored in a memory 33. The detected average densities of the peripheral parts of the four sides are compared with a predetermined reference range, and the average density within the predetermined reference range is selected. The peripheral part image density processing part places the peripheral part corresponding to the selected average density at the top, reads out the digital image signal from the memory, and forms the image for one page from the top.
Additionally, in addition to the above described method for preventing paper jam, for example, a method is used that is disclosed in Japanese Patent Laid-Open No. 2001-341400. In the method, image information for each page is read out from the image information stored in a document memory, and the amount of the image information of a predetermined region on the leading edge of the read image information for one page in the paper carriage direction is compared with the amount of the image information of a predetermined region on the rear edge side thereof. When the amount of the image information of a predetermined region on the leading edge is larger than the amount of the image information of a predetermined region on the rear edge side, an image information output to a printing part is reversed by 180°. Thus, the image information at the leading edge of the paper is reduced, and the frequency of occurrence of a paper rolled-in jam is reduced.
However, in the above described method for preventing paper jam disclosed in Japanese Patent Laid-Open No. 2001-026162, the following problems remain: (1) it is required to constantly measure the density; (2) there is a possibility that bit map data is turned even in the case of not being required to be turned.
Additionally, for the color MFP, in consideration of reuse of components (referred to as object, hereinafter) of a document, a storing means is proposed that stores information in a storage unit in the color MFP not by the document unit but by each object.
In the above constitution, since a user who reuses the object is not limited to a creator of the object, there is a possibility that other users use the object. When the toner application amount of the object (the toner amount applied for the object) is large and the printing position of the object is set to the leading edge of the paper, paper jam is likely to occur.
That is, there remains another problem (3) that other users must know, in advance, the possibility that the object causes paper jam.